Psittacosaurus
Psittacosaurus is a genus of extinct ceratopsian dinosaur from the Early Cretaceous of what is now Asia, existing between 123.2 and 100 million years ago. It is notable for being the most species-rich dinosaur genus. Up to 11 species are known, from across Mongolia, Siberia, China, and possibly Thailand. Information The species of Psittacosaurus were obligate bipeds at adulthood, with a high skull and a robust beak. One individual was found preserved with long quills on the tail, similar to those of Tianyulong, yet scales of varying sizes and shapes across the rest of the animal. Psittacosaurus probably had complex behaviours, based on the proportions and relative size of the brain. It may have been active for short periods of time during the day and night, and had good smell and well developed vision. Psittacosaurus was one of the earliest ceratopsians, but closer to Triceratops than Yinlong. Once in its own family, Psittacosauridae, with other genera like Hongshanosaurus, it is now considered to be senior synonym of the latter and an early offshoot of the branch that led to more derived forms. The genera closely related to Psittacosaurus are all from Asia, with the exception of Aquilops, from North America. The first species was either P. lujiatunensis or closely related, and it may have given rise to later forms of Psittacosaurus. Psittacosaurus is one of the most completely known dinosaur genera. Fossils of over 400 individuals have been collected so far, including many complete skeletons. Most different age classes are represented, from hatchling through to adult, which has allowed several detailed studies of Psittacosaurus growth rates and reproductive biology. The abundance of this dinosaur in the fossil record has led to the labeling of Lower Cretaceous sediments of east Asia the Psittacosaurus biochron. The integument, or body covering, of Psittacosaurus is known from a Chinese specimen, which most likely comes from the Yixian Formation of Liaoning Province, China. The specimen, which is not yet assigned to any particular species, was illegally exported from China, in violation of Chinese law, but was purchased by the Senckenberg Museum in Germany. It was described while awaiting repatriation. Most of the body was covered in scales. Larger scales were arranged in irregular patterns, with numerous smaller scales occupying the spaces between them, similarly to skin impressions known from other ceratopsians, such as Chasmosaurus. A series of what appear to be hollow, tubular bristle-like structures, approximately 16 centimeters long, were also preserved, arranged in a row down the dorsal (upper) surface of the tail. These were confirmed by the authors, as well as an independent scientist, to not represent plant material. The bristle-like integumentary structures extend into the skin nearly to the vertebrae, and were likely circular or tubular before being preserved. Under ultraviolet light, they gave off the same fluorescence as scales, providing the possibility they were keratinized. The study stated that, "at present, there is no convincing evidence which shows these structures to be homologous to the structurally different integumentary filaments of theropod dinosaurs". However, they found that all other feather-like integument from the Yixian Formation could be identified as feathers. In 2008, another study was published describing the integument and dermis of Psittacosaurus sp., from two different specimens. The skin remains could be observed by a natural cross-section to compare them to modern animals, showing that dinosaurian dermal layers evolved in parallel to those in many other large vertebrates. The collagen tissue fibres in Psittacosaurus are complex, virtually identical to all other vertebrates in structure but having an exceptional thickness of about forty layers. As the sections of dermis were collected from the abdomen, where the scales were eroded, the tissue may have assisted with the musculature of the stomach and intestines and offered protection against predators. As described in a 2016 study, examination of melanosomes preserved in the specimen of Psittacosaurus preserved with integument indicated that the animal was countershaded, likely due to preferring a habitat in dense forests with little light, much like many modern species of forest-dwelling deer and antelope; stripes and spots on the limbs may represent disruptive coloration. The specimen also had dense clusters of pigment on its shoulders, face (possibly for display), and cloaca (which may have had an antimicrobial function), as well as large patagia on its hind legs that connected to the base of the tail. Its large eyes indicate that it also likely had good vision, which would have been useful in finding food or avoiding predators. The authors pointed out that there might have been variation in coloration across the range of the animal, depending on differences in the light environment. The authors were unable to determine which species of Jehol Formation Psittacosaurus the specimen belonged to due to the way the skull is preserved, but ruled out P. mongoliensis, based on hip features. Another 2016 study used laser-stimulated fluorescence imaging to analyze the internal structure of the bristles. The highly cornified bristles are arranged in tight clusters of three to six individual bristles, with each bristle being filled with pulp. The authors considered the bristles as being homologous to the quills of Tianyulong, the elongated broad filamentous feathers (EBFFs) of Beipiaosaurus, and possibly the feathers of birds as well. Similar bristles are found in extant birds such as the horned screamer; these structures differ from feathers in that they do not develop from a follicle, but both arise from discrete cell populations. A darkened soft-tissue structure was also found near the jugal horn; this may represent a keratinous sheath or a skin flap. In-Game Psittacosaurus will be in the early access of Prehistoric Kingdom. One skin, nicknamed "Dust Bath", is based on the 2016 discovery. Gallery Psittacosasurus all skins.jpg Psittacosaurus_01_Preview.png|Dust Bath Psittacosaurus_02_Preview.png|Progeny Psittacosaurus_03_Preview.png|Terracotta Category:Dinosaurs Category:Herbivore Category:Ceratopsian